import pygame
from pygame import locals
import random

# 初始化pygame，为使用硬件做准备
pygame.init()

screen = pygame.display.set_mode((660, 480))
FPSCLOCK = pygame.time.Clock()  

background = pygame.image.load('bg.png')
right = pygame.image.load('right.png')      
food = pygame.image.load('apple.png')      
body = pygame.image.load('body.png')        
left = pygame.image.load('left.png')        
up = pygame.image.load('up.png')           
down = pygame.image.load('down.png') 
my_font = pygame.font.Font('neuropol.ttf',18)     
x, y = 240, 120
position = [(180, 90), (180, 120), (210, 120), (x, y)]
apple_x = 360
apple_y = 300

setheading = "right"
snake_head = right
score = 0

while True:
    for event in pygame.event.get():
        if event.type == locals.QUIT:
            # 接收到退出事件后退出程序
            exit()
        if event.type == locals.KEYDOWN:
            if event.key == locals.K_RIGHT and setheading != "left":
                setheading = 'right'
                snake_head = right
            if event.key == locals.K_LEFT and setheading != "right":
                setheading = 'left'
                snake_head = left
            if event.key == locals.K_UP and setheading != "down":
                setheading = 'up'
                snake_head = up
            if event.key == locals.K_DOWN and setheading != "up":
                setheading = 'down'
                snake_head = down

    if setheading == "right":
        x += 30
    elif setheading == "left":
        x -= 30
    elif setheading == "up":
        y -= 30
    else:
        y += 30
    if x == apple_x and y == apple_y:
        num1 = random.randint(1,22)
        num2 = random.randint(1,16)
        apple_x = 30*num1-30 
        apple_y = 30*num2-30
        score += 10
    else:
        position.pop(0)    
    if x < 0 or x > 630 or y < 0 or y > 450:
        exit()
    position.append((x, y))
    screen.blit(background, (0, 0))
    screen.blit(snake_head, position[-1])
    for i in range(len(position)-1):
        screen.blit(body, position[i])
    screen.blit(food, (apple_x,apple_y))
    info = 'Score'+str(score)
    text = my_font.render(info, True, (0,0,0))
    screen.blit(text,(540,10))
    pygame.display.update()
    FPSCLOCK.tick(3)